Low Infection Type

Environmental Variability

Origin

Pathogenic Variability

The international survey of Huerta-Espino (1992) as well as parhogenicity surveys in the USA (Roelfs et al., 1991), Canada (Harder and Dunsmore, 1990), Mexico (Singh, 1991), South Africa (Le Roux and Rijkenberg, 1987a) and Australia (RF Park, unpublished 1992) failed to find virulence.

Reference Stocks

i: W3531, a Chinese Spring stock produced by ER Sears and involving a translocation to chromosome 2A (RA McIntosh, unpublished 1974). This stock is characterised by having adhering glume fragments, especially in the crease region of the grain. This primitive feature tends to be associated with the absence of at least a part of wheat chromosome 2A. C77.19, a CS/T. speltoides derivative, is a cleaner threshing line with Sr32 present in chromosme 2B. Sears later produced four further transfers with Sr32 present in chromosomes 2B and 2D. These are accessioned in The University of Sydney cytogenetics collection as C82.1 (chromosome 2B), C82.2 (2D), C82.3 (2D) and C82.4 (2D). The lines designated CS Sr32 (Le Roux and Rijkenberg, 1987b) and ER 5155 (Roelfs and Martens, 1988) probably correspond to W3531 or C77.19.

Source Stocks

Australian backcross lines produced at The University of Sydney Plant Breeding Institute.

Use in Agriculture

Early breeding studies at The University of Sydney using W3531 failed to separate resistance from the adherent glume phenotype. Backcross derivatives with Sr32 derived from C77. 19 were produced and distributed to wheat breeders but no line was commercialised or used in further breeding. The reasons for this are unknown. Sears (pers. comm. 1982) suggested that C82.2 was the most normal of the translocation lines.

Breeder's Toolbox

Ug99 Effectiveness:-Unsuitable for utilization due to linkage with undesirable traits in the translocationSource:RustTracker.org

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Dundas and others (unpublished) recently developed several recombinant translocation stocks with reduced Aegilops speltoides chromatin harboring Sr32 on chromosome 2DS. DNA markers have not been reported for these new lines, but several laboratories have identified markers that successfully identify the original translocation. Deployment of Sr32 has not been reported, but several programs are actively using the new translocation derivatives in resistance breeding efforts.Source: Mike Pumphrey, BGRI 2012 Presentation: Stocking the Breeder's Toolbox